Keep in mind that's likely not related to the dB sound pressure level in air that we're all familiar with. dB is a logarithmic ratio to pressure to a reference.

Keep in mind that's likely not related to the dB sound pressure level in air that we're all familiar with. dB is a logarithmic ratio to pressure to a reference. In air, that reference is 20µPa, acoustic pressure in water typically uses a different reference (1µPa). There is also an adjustment of 36 dB to account for the higher impedance of water. So 235 dB in water is roughly 173 dB SPL -- still loud, but many orders of magnitude lower. [0] https://fas.org/man/dod-101/sys/ship/acoustics.htm https://fas.org/man/dod-101/sys/ship/acoustics.htm